When you see "total noise" as you put it... can you confirm you see the same thing on the camera LCD screen.  It should be the same. Nikon cameras do not work the same as Canon where the later has an "Exposure Simulation" feature and works relatively well.  Nikon on the other hand it is hit and miss.  Older Nikon do not allows changing values while in live view; you need to pause liveview in BYN, make your changes, and resume live view.  Make sure you select a time value < 2 second,